Lamp base



FIG. 1 is a perspective view of a lamp base showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof; and

FIG. 4 is a perspective view of a second embodiment of my new design, this embodiment being identical to the first except for the omission of the light fixture stanchion. 

The ornamental design for a lamp base, as shown and described. 